Should farmers lower planting populations?
Higher plant populations are a trend farmers have followed in recent years to boost corn yields. But in 2012 that practice appeared to backfire in some drought-hit areas. There, producers with lower plant populations often harvested better yields because fewer plants meant less competition for available moisture. The obvious question: Should farmers in dry areas lower their plant populations in 2013?
"Plant populations need to stay about where they are," advises Steve Gauck, a team sales agronomist for Beck’s Hybrids.
"You can make minor changes, that’s fine, but don’t make huge adjustments just because Mother Nature threw us a curveball last year," he adds.
Don’t make huge adjustments just because Mother Nature threw us a curveball last year
Darren Hefty agrees. "If it shapes up to be a dry season, you might back off populations a tick, say 500 plants, but be cautious—you don’t want to go overboard," says Hefty, co-owner of Hefty Seed Company, Baltic, S.D., with his brother, Brian.
The most important considerations in any year are to understand the hybrids you selected, the type of ground they perform in best, and what agronomic practices will coax the most yield out of each one, says Ken Ferrie, Farm Journal Field Agronomist.
"It’s important to evaluate the strengths and weaknesses of each hybrid and manage for both," he notes.
Because corn growers have different soil types, row configurations, fertility programs and overall yield environments, Mike Kavanaugh, AgriGold agronomy manager, says that such criteria should be matched to their hybrids.
"It’s a fact that some genetics prefer higher populations and some don’t, and that perfect growing conditions can maximize yield. But when extreme hot, dry conditions occur, all genetics are susceptible to plant cannibalization, which creates another set of issues," Kavanaugh says. "Make sure you know the limits of your hybrids."
Sun block. University of Illinois agronomist Fred Below doesn’t disagree with Kavanaugh but says higher corn populations can prove to be a benefit in a dry year.
The reason is that more corn plants in the field absorb more sunlight, even if plant leaves are rolled. That sunlight translates to more yield.
"In our 2012 test plots, we still wound up with higher yields in dry conditions—15 bu. to 20 bu. more per acre—with the higher plant populations," Below says. "The key was intensive management of the crop." Below’s definition of intense management includes banding fertilizer for efficient uptake, crop rotation, and using high-tech hybrids and fungicides.
Extreme heat at pollination last year sapped corn yields as much as the drought, Kavanaugh says. "In each area, planting date along with hybrid maturity made a huge difference in yield outcome," he notes.
"You could see a 100-bu. difference between maturities in any given latitude depending on whether the hybrid was shooting or pollinating before, during or after those 105° temperatures we had," he adds.
Gauck saw similar scenarios in southern Indiana and Kentucky and says farmers need to plant a variety of maturities and spread planting dates so pollination doesn’t occur at one time. He advises farmers in a cornsoybean rotation to plant some of their corn acres, switch to soybeans and then return to corn to finish up.
Whether to flex. This past fall, Hefty says, he got questions from corn growers about whether to plant more flexstyle hybrids to hedge against drought.
"Flex-style hybrids are not an automatic solution to dry weather," he says.
Peter Thomison, Ohio State University Extension agronomist, agrees.
"Ear type must be considered in conjunction with overall hybrid performance," Thomison says. "Select a hybrid for its performance, not because it possesses a particular trait or characteristic like flex or fixed ear size."
You can e-mail Rhonda Brooks at email@example.com.